Fibromuscular dysplasia is an non inflammatory non atherosclerotic obstructive arterial disease affecting mid-size arteries. It is considered as a rare vascular disease of unknown origin. Fibromuscular dysplasia may become symptomatic depending on location and severity of narrowing of the arterial lumen. for example,when a stenosis develops within a renal artery, arterial hypertension may develop. The cause of fibromuscular dysplasia is unknown. Several factors have been suggested to be associated with it: tobacco abuse or oestrogens. In order to progress into identifying possible causative mechanisms of the disease, we design a pathophysiology study destined to assess endothelial function in patients with fibromuscular dysplasia and to identify possible plasmatic biomarkers of the disease.